JPWO2011045974A1 - Implantable flow sensor - Google Patents

Abstract

A state in which the flexible base material on which the heater is formed is mounted in a pipe arranged along a tubular organ in the living body through which the medium flows, and the amount of heat generated from the heater of the mounted flexible base material is transmitted to the medium. It is a flow rate sensor that measures the flow rate of a medium flowing through a tubular organ in a living body by detecting the flow rate. In the flow sensor, each of the two or more heaters formed on the flexible base has a symmetrical structure having the same heating performance under the same conditions, and the linear shape supplies power to each heater from outside the living body. The members have a symmetrical structure having the same heating performance under the same conditions, so that the heat distribution by the heater and the linear member in the pipe is symmetric. Further, the plurality of linear members protrude from the tubular organ so as to intersect the outside of the living body.

Description

  The present invention relates to a biological implantable flow sensor capable of detecting the flow rate of a medium such as gas or liquid flowing in a tubular organ of a living body.

2. Description of the Related Art Conventionally, there is a flow sensor having a structure in which a heater is formed on a flexible base material and the flexible base material is mounted on a pipe inner wall so as to follow the pipe inner wall shape. This flow sensor is manufactured on a film with a thickness of several microns and is mounted on the inner wall surface of the pipe where the flow velocity is the smallest, so the increase in fluid resistance associated with the sensor installation can be reduced to the limit. There is a feature (see, for example, Patent Document 1). There is also a technique for downsizing the flow sensor with a heat shrinkable tube (see, for example, Patent Document 2).
JP 2007-127538 A JP 2009-168480 A

  However, the flow sensors described in Patent Document 1 and Patent Document 2 are configured to incorporate a flow sensor into a catheter structure, and measure the flow rate of a medium in the tubular organ by embedding the flow sensor in a tubular organ of a living body. For example, it cannot be implanted in the respiratory tract of a rat for animal experiments. Further, in the conventional flow rate sensor of the catheter structure, since the electrical wiring to the sensor extends along the fluid flow direction in the pipe, the sensor output characteristic with respect to the flow rate depends on the direction of the fluid flow in the pipe. There is a problem that the output value when flowing from the upstream side and the output value when flowing from the downstream side are different, and the reciprocating flow such as exhaled breath cannot be measured accurately.

  The embodiment will be described in detail below. In Patent Document 1, it is described that “extraction of the electrode to the heater is performed by bending a part of the flexible board on which the heater is formed, outside the pipe at the end of the pipe through which the fluid flows”. Further, according to the description of the accompanying drawings of the application, “the thin film wiring connected to the heater is formed on the flexible substrate like the heater and the wiring is taken out from one direction of the piping”.

  For this reason, in Patent Document 1, “the power supply to the heater is first taken out from one direction of the pipe by thin film wiring in the pipe, and finally bent at the pipe end and connected to the outside. Because of the “configuration,” there is a phenomenon that the sensor output characteristics differ between when the fluid in the pipe flows from the upstream side and when flowing from the downstream side.

  Since Patent Document 2 basically has the same structure as Patent Document 1, “the thin-film wiring for supplying power to the heater is taken out from one direction of the pipe inside the pipe”. Has occurred.

  Reason for this reason: “When the wiring that supplies power to the heater is in the pipe and is structured to take out the thin film wiring from one direction of the pipe, the reciprocating flow of the medium in the pipe cannot be measured accurately” As a result of detailed examination, it was possible to consider as follows.

  That is, since the thin film wiring for supplying electric power to the heater also has an electrical resistance value, the thin film wiring portion performs a function similar to that of the heating element although it is slight. Therefore, when the thin film wiring is taken out from the flow direction of the fluid in the pipe as described above with respect to the heater, the thin film wiring also becomes a heating element, so that the heat distribution on the heater becomes asymmetric, and as a result, flows through the pipe. The output characteristics of the sensor change depending on the direction of the fluid.

  As a result, there is no problem if the flow rate is measured only in one direction of flow, but when applied to reciprocating flow measurement such as exhalation, the sensor output value differs depending on the direction of fluid flow, and the flow rate of fluid There was a problem that it was not possible to measure accurately.

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a living body implantable flow sensor that can be embedded in a living tubular organ and can accurately measure the flow rate of a medium in the tubular organ.

The living body implantable flow sensor of the first aspect of the present invention, which has been made to achieve the above object, has a flexible base material in which a heater is formed in a pipe arranged along a tubular organ in a living body through which a medium flows. A flow rate sensor that measures the flow rate of a medium flowing in a tubular organ in a living body by detecting a state in which the amount of heat generated from the heater of the mounted flexible base material is transmitted to the medium,
Each of the two or more heaters formed on the flexible substrate has a symmetrical structure having the same heating performance under the same conditions, and a linear member that supplies power to the heaters from the outside of the living body. By configuring a symmetrical structure having the same heating performance under the same conditions, the heat distribution by the heater and the linear member in the pipe is configured to be symmetric,
The plurality of linear members protrude from the tubular organ so as to intersect the outside of the living body.

  In the above configuration, two or more heaters formed on the flexible base material for flow rate measurement have a symmetrical structure with the same heating performance under the same conditions, and power is supplied to each heater from outside the living body. Since the linear member is configured to have a symmetrical structure having the same heating performance under the same conditions, the heat distribution by the heater and the linear member in the pipe is configured to be symmetrical. Regardless of the direction of the flow of the medium, the sensor output characteristics with respect to the flow rate of the medium flowing in the pipe can be made the same, and as a result, the reciprocating flow such as exhaled breath can be accurately measured. In addition, when the flexible base material is mounted on the inner wall of the tubular organ in the living body so as to follow the shape of the inner wall of the tubular organ in the living body, the fluid resistance accompanying the installation of the sensor can be reduced to the limit.

  In addition, “a plurality of heaters have the same heating performance under the same conditions” means, for example, when a plurality of heaters are formed of the same material and have the same size and shape. Yes, if the materials are different, the same size or shape may be included. In addition, the structure “the linear member has the same heating performance under the same conditions” means the same content as the structure of the heater.

  Since the plurality of linear members protrude from the tubular organ so as to intersect the outside of the living body, power can be supplied from the outside of the living body to the heater on the flexible substrate via the plurality of linear members. . Thereby, for example, even if it is embedded in a tubular organ in a living body such as a human being or an animal, signals can be exchanged from the outside to the sensor in the sensor portion. In addition, as a tubular organ in a living body, in addition to an airway through which air flows as a medium, a blood vessel through which a liquid flows as a medium, a ureter, or an intestinal tract through which a solid fluid flows can be considered.

  By the way, various methods are conceivable for supplying power to the linear member from the outside. However, since the power is supplied from the outside to the plurality of linear members by wire or wirelessly, the linear member is not generated. It is good to be comprised so that it may penetrate the tubular organ in a body and the exterior of the said biological body.

In this way, since power can be supplied from the outside, the flow rate of the medium in the tubular organ in the living body over a long period of time can be measured without being limited by the capacity of the battery.
Note that the “wire member that supplies power by wire” means, for example, a power wire such as a copper wire or an aluminum wire that is coated so as not to adversely affect the living body as much as possible. The “linear member for supplying power” means, for example, a linear or loop antenna (antenna).

  In addition, since the living body has working parts such as limbs, mouths, and tails, the linear member may be destroyed by the working parts when detecting the flow rate of the medium in the tubular organ. Therefore, as in the second aspect of the present invention, it is desirable that the portion of the linear member that protrudes to the outside of the living body is in a position where the operating part of the living body is difficult to contact.

  Furthermore, if the portion of the linear member that protrudes outside the living body is positioned so as not to be broken by the living body working site, the linear member is broken by the living body working site during the flow measurement of the medium in the tubular organ. This is convenient.

  Further, as in the third aspect of the present invention, the position where the biological implantable flow sensor is installed is an animal trachea, and the electrical wiring member connected to the linear member is connected to the animal from the back. Take out to the outside.

  When the living body implantable flow sensor is installed in the trachea in this way, the linear member is taken out so as to protrude from the trachea, and the electrical wiring member connected to the linear member is After being drawn to the back, it is preferably taken out of the animal from the back.

It is a figure which shows the usage concept of the embedding type small flow sensor of this embodiment. It is a figure which shows the structure of the embedding type small flow sensor which embodied this embodiment. It is a figure which shows the connection method of the thin film wiring of a film substrate used for the embedding type small flow sensor of this embodiment, and a wire-like electric wiring. It is a figure which shows the photograph of the film-form flow sensor of this embodiment. It is a figure which shows the method of reducing in size the outer diameter of several millimeters or less which can embed the embedding type small flow sensor of this embodiment. It is a figure which shows the mode of mounting of the embedding type small flow sensor of this embodiment. It is a figure which shows the example of a relationship between the input electric power of the flow sensor of this embodiment, and a detected flow volume. It is a figure which shows the relationship between the temperature distribution on a heater, the flow volume, and a sensor output in the case of the electrical wiring taking-out structure in the conventional type flow sensor (conventional sensor) as a comparative example. It is a figure which shows the relationship between the temperature distribution on a heater, the flow volume, and a sensor output in the case of the electrical wiring extraction structure in the flow sensor of this embodiment. It is a figure which shows the mode of mounting when the implantable small flow sensor of this embodiment is embedded in the rat which is an experimental animal. It is a figure which shows the result when the exhalation inhalation characteristic in the airway at the time of rat activity is directly evaluated with the flow sensor after the implantable small flow sensor of this embodiment is embedded in the airway of the rat.

  DESCRIPTION OF SYMBOLS 1 ... Laboratory animal, 2 ... Airway (tubular organ), 3 ... Implantable small flow sensor, 4 ... Wire-like electric wiring (electric wiring member), 5 ... Film-like flexible electric wiring, 10 ... Film-like flow sensor, 11 DESCRIPTION OF SYMBOLS ... Film substrate, 12 ... Heater, 13 ... Thin film wiring (linear member), 15 ... Anisotropic conductive film, 20 ... Thermal insulation cavity structure, 21 ... Flow path, 30 ... Piping, 40 ... Alignment jig, 41 ... groove, 42 ... resin film, 50 ... heat-shrinkable tube, 51 ... slit for taking out wiring.

Hereinafter, the best mode for carrying out the present invention will be described in more detail.
FIG. 1 shows a usage concept of an embedded small flow sensor according to an embodiment of the present invention. The implantable small flow sensor 3 is implanted in the airway 2 of the experimental animal 1 such as a rat and a mouse, and the expiratory inspiration state during the activity of the experimental animal 1 is quantitatively measured and evaluated by the implantable small flow sensor 3.

  The exchange of electrical signals between the implantable small flow sensor 3 and the outside uses a wire-like electrical wiring 4 connected to the implantable compact flow sensor 3, and this wire-like electrical wiring 4 is under the skin of an experimental animal. Turn to the back and take out to the outside.

  This prevents the experimental animal 1 from scratching the wire-like electrical wiring 4 with the working part of the animal's hand, foot, mouth or tail when measuring and evaluating the state of exhaled breathing during activity. The wire-like electric wiring 4 is not destroyed by the operation site such as an animal hand.

  It should be noted that the outer diameter of the implantable small flow sensor is preferably determined in accordance with the size of the airway 2 of the experimental animal to be applied. For example, in the case of a mouse, the outer diameter of the implantable small flow sensor is preferably about 1.5 mm to 1.8 mm, and in the case of a rat, it is preferably about 1.8 mm to 2.0 mm.

Next, FIG. 2 shows the structure of an embedded small flow sensor according to an embodiment of the present invention.
The embedded small flow sensor 3 includes a film-like flow sensor 10, a thermal insulation cavity structure 20, a flow path 21, and a pipe 30 arranged along the inner wall of the pipe. The film-like flow sensor 10 includes a heater 12 on a film substrate 11 and a thin film wiring 13 that supplies electric power to the heater. The film substrate 11 is disposed along the inner wall of the pipe 30, thereby reducing the turbulence of the flow of the fluid flowing through the flow path 21 in the pipe 30 due to the installation of the sensor 10 in the pipe 30 to the utmost. Yes.

  Further, the two sets of heaters 12 and the thin film wirings 13 formed on the film substrate 11 are both in the same shape and have a symmetrical structure having the same heating performance under the same conditions. The heat distribution by the heater 12 and the thin film wiring 13 is configured to be symmetric.

  Further, the thin film wiring 13 is arranged so as to protrude from the airway which is a tubular organ to the outside of the living body. Specifically, even if the direction of flow is reversed, the two sets are taken out from the inside of the pipe 30 so as to intersect (perpendicular) with respect to the flow of the fluid flowing through the flow path 21 in the pipe 30. The heater 12 and the thin film wiring 13 are inverted under the same conditions. Thereby, the sensor output characteristic with respect to the flow rate becomes the same without depending on the direction of the medium flow in the pipe 30.

  In addition, a wire-like electrical wiring 4 is connected to an end portion of the thin film wiring 13 provided on the film substrate 11 using an anisotropic conductive film 15. As a result, even when the implantable small flow sensor 3 is embedded in the airway of an animal, the wire-like electrical wiring 4 can be easily routed to the back portion under the skin, and reliability can be obtained even after taking out from the back portion. High wiring extraction is possible.

  In addition, it is desirable to determine the diameter to be applied in consideration of the possibility that physical tension is applied to the wire-like electric wiring 4. In addition, the thin film wiring 13 connected to the wire-shaped electric wiring 4 (electric wiring member) through the anisotropic conductive film 15 functions as a linear member for supplying electric power to the heater 12 of the embedded small flow sensor 3. doing.

  In the embedded small flow sensor 3, in order to insulate the heater 12 formed on the film substrate 11, a heat insulating cavity structure 20 is formed on the outer periphery of the heater. In order to form the thermal insulation cavity structure 20, the pipe 30 of the embedded small flow sensor 3 has a double structure made of a resin material. Thereby, the heat insulation with respect to a heater board | substrate is achieved, and it becomes possible to measure respiration 10-20 times in 1 minute.

  Further, the portion where the thin film wiring 12 and the wire-like electric wiring 4 are connected using the anisotropic conductive film 15 is further provided with a cylindrical structure made of a resin material on the outer side, and fluid does not leak from this portion. Only the wire-like electric wiring 4 is taken out to the outside.

  FIG. 2 shows a case where the flow rate in the pipe and the direction thereof are detected using two sets of heaters. However, depending on the application, one heater and a sensor for detection outside are provided. There is also a method of providing. In this case, the measurable flow rate range becomes narrow, but on the other hand, it has a feature that the flow rate can be measured with high accuracy at a small flow rate.

  Moreover, although the case where the cylindrical pipe | tube was used was shown in FIG. 2, even if it is a pipe | tube (for example, ellipse and square cross section) of shapes other than this, this sensor utilizes the flexibility of the film substrate 11, It can be deformed according to the inner wall structure of the tube and adapted to the inner wall. Therefore, it is desirable to change the sensor form installed on the inner wall of the pipe according to the shape of the pipe to be measured.

Next, FIGS. 3A to 3D show a connection method between the thin film wiring of the film substrate and the wire-like electric wiring used in the embedded small flow sensor of the present embodiment.
3A, first, the wire-like electric wiring 4 is inserted into the groove 41 provided in the positioning jig 40, and the wire-like electric wiring 4 is fixed. In order to prevent the anisotropic conductive film 15 from sticking to the alignment jig 40 in the final connection step, a resin film 42 is provided below the wire-like electrical wiring 4 at the connection location. Keep it.

  In addition, about the resin film 42, it is desirable to determine the material according to an application destination. Further, a part of the wire-like electric wiring 4 at the connection location is removed from the insulating coating in order to make an electrical connection with the thin film wiring 13 formed on the film substrate 11 with the anisotropic conductive film 15.

In FIG. 3B, the anisotropic conductive film 15 is placed on the wire-like electrical wiring 4 at the connection location.
In FIG. 3C, the thin film wiring 13 provided on the film substrate 11 is arranged so that the thin film wiring 13 is on the anisotropic conductive film side, and the thin film wiring 13 and the wire-like electric wiring 4 at the connection location are electrically connected. Align so that Finally, the connection portion is brought into close contact by thermocompression bonding, and the thin film wiring 13 and the wire-like electric wiring 4 are physically and electrically connected. The heater 12 and the thin film wiring 12 on the film substrate 11 are produced using a metal thin film forming technique and a photolithography technique.

FIG. 3D shows an overview of the film flow sensor 10 produced by the above method.
A photograph of the film flow sensor of the present invention is shown in FIG. An enlarged photograph of the heater part is shown on the upper side in FIG.

  FIG. 4 shows a case where the heater 12 and the thin film wiring 13 are formed of chromium (50 nanometers) and gold (250 nanometers) on a resin film having a thickness of several microns. FIG. 4 shows the case where the flow rate in the pipe and the direction thereof are detected using two sets of heaters. However, one heater and a sensor for detection are provided on both sides according to the application. There is also a method of providing. In this case, the measurable flow rate range becomes narrow, but on the other hand, it has a feature that the flow rate can be measured with high accuracy at a small flow rate.

  Next, FIGS. 5A to 5F show a method of downsizing the embedded small flow sensor according to the present embodiment to an outer diameter of several millimeters or less that can be embedded. In the present embodiment, the heat-shrinkable resin tube is used to mount the film flow sensor 10 on the inner wall of the pipe, and the size is designed to be several millimeters or less. Details are described below.

  In FIG. 5A, first, heat shrinkable tubes 50 are inserted on both sides of the heater 12 of the film flow sensor 10. In this case, the size of the heat-shrinkable tube is relatively large, for example, an inner diameter of 1.27 millimeters, and the heat-shrinkable tube 50 can be inserted on both sides of the film flow sensor 10.

  A cross-sectional view when the heat-shrinkable tube 50 is inserted on both sides of the film flow sensor 10 is shown on the right side of FIG. 5A. In this method, the film flow sensor 10 does not have to be along the inner wall of the pipe at the time of insertion, and the heat shrinkable tubes 50 may be simply inserted on both sides of the heater 12 of the film flow sensor 10, which is an easy operation. Yes. In addition, the heat shrinkable tube 50 is not provided in the portion of the heater 12, and as a result, this portion finally becomes the cavity structure 20 for thermal insulation.

  Moreover, the wire-like electric wiring 4 provided in the film-like flow rate sensor 10 is taken out from between the heat-shrinkable tubes 50 to the outside. In addition, it is desirable that the size and material of the heat-shrinkable tube and the size of the flow rate sensor are appropriately determined according to usage conditions.

  In FIG. 5B, heat is applied to the heat-shrinkable tubes 50 provided on both sides of the heater 12 of the film-like flow rate sensor 10, and the heat-shrinkable tubes 50 are shrunk to a desired size. At this time, as the heat shrinkable tube 50 contracts, both end portions of the film flow sensor 10 are automatically mounted along the inner wall of the tube.

  In FIG. 5C, the heat shrinkable tube 50 is prepared again, and the heat shrinkable flow rate sensor tube formed in the previous step is inserted therein. Unlike the previous tube, this tube is provided with a slit 51 for taking out the electrical wiring to a part of the heat shrinkable tube 50.

  In FIG. 5D, heat is applied again to shrink the outer heat-shrinkable tube 50 and close contact with the inner tube to form the thermal insulation cavity structure 20. Further, in the process of contracting the tube, the slit 51 is closed with the electric wiring film portion interposed therebetween.

  In FIG. 5E, for the purpose of physically protecting the connecting portion between the thin film wiring 12 and the wire-like electric wiring 4 by the anisotropic conductive film 15, the heat shrinkable tube that covers only the connecting portion is again covered. 50 is prepared, and the heat shrinkable flow rate sensor tube formed in the previous step is inserted.

  In FIG. 5F, heat is applied again to shrink the heat-shrinkable tube for protecting the wiring connection, and the inner tube is brought into close contact so that only the wire-like electric wire 4 is exposed from the heat-shrinkable flow sensor tube. To do.

  By using the process as described above, the two sets of heaters 12 and thin film wirings 13 provided on the flexible substrate 11 have the same shape, and the thin film wirings 13 correspond to the flow of fluid flowing through the flow path 21. Even when the flow direction is reversed, the two heaters 12 and the thin film wiring 13 are reversed under the same conditions. As a result, the sensor output characteristics with respect to the flow rate become the same regardless of the flow direction, and as a result, the reciprocating flow such as exhaled breath can be accurately measured.

  Moreover, the connection location of the thin film wiring 12 and the wire-like electric wiring 4 by the anisotropic conductive film 15 is protected by the heat-shrinkable tube 50, and only the wire-like electric wiring 4 is exposed from the heat-shrinkable flow sensor tube. Even when the implantable small flow sensor 3 is embedded in an animal's respiratory tract, the wire-like electrical wiring 4 can be easily routed to the back part under the skin, and the machine It is possible to take out the wiring with high reliability against the mechanical load.

  FIG. 6 shows how the embedded small flow sensor of the present invention is mounted. As explained above, only the wire-like electrical wiring 4 is exposed from the heat-shrinkable flow sensor tube, so that it can be easily embedded in the animal's airway.

  Next, an example of the relationship between the input power and the detected flow rate of the flow rate sensor of this embodiment is shown in FIG. FIG. 7 shows the input power to the sensor bridge circuit with respect to the flow rate when the heater element itself is used as a flow rate sensor. As shown in FIG. 7, the input power changes according to the flow rate. By using this as a calibration curve, an unknown flow rate can be calculated by this sensor.

  Here, as a comparative example, FIGS. 8A to 8C show the electrical wiring extraction structure in the conventional flow sensor (conventional sensor), the temperature distribution around the heater, and the relationship between the flow rate and the sensor output. FIG. 8A is a diagram showing an electrical wiring extraction structure in a conventional sensor, FIG. 8B is a conceptual diagram of a temperature distribution around the heater and a measurement result, and FIG. 8C is a graph showing the flow rate and sensor output. It is the figure which showed the relationship.

  As shown in FIG. 8A, in the conventional form, the thin film wiring 113 for supplying power to the heater 112 has a structure taken out from one direction of the pipe inside the pipe. Therefore, as shown in FIG. 8B, the heat distribution on the heater is asymmetric.

  As a result, as shown in FIG. 8C, a phenomenon has occurred in which the output value of the sensor varies depending on the direction of the fluid flowing in the pipe. This is because, since the thin film wiring 113 that supplies power to the heater 112 has an electrical resistance value, the thin film wiring 113 also becomes a heating element to a slight extent. If the wiring 113 is taken out from the flow direction of the fluid in the pipe, the heat distribution on the heater 112 becomes asymmetric due to heat generation of the thin film wiring 113, and as a result, the output characteristics of the sensor change depending on the direction of the fluid flowing through the pipe. It is.

  On the other hand, the flow sensor of the present embodiment has a thin-film wiring structure that overcomes the above problems. 9A to 9C show the electrical wiring extraction structure in the flow rate sensor of the present embodiment, the temperature distribution around the heater, and the relationship between the flow rate and the sensor output. FIG. 9A is a diagram showing an electrical wiring take-out structure in the present embodiment, FIG. 9B is a conceptual diagram of temperature distribution around the heater and a measurement result, and FIG. FIG.

  As shown in FIG. 9A, in this embodiment, the two sets of heaters 12 and the thin film wirings 13 are both in the same shape and have a symmetrical structure having the same heating performance under the same conditions. The heat distribution by the heater 12 is configured to be symmetrical, and the thin film wiring 13 is taken out from the pipe so as to intersect the flow of the fluid flowing through the flow path.

  As a result, the heat distribution on the heater is symmetric as shown in FIG. 9B. As a result, the sensor output characteristics with respect to the flow rate are not dependent on the direction of the fluid flowing in the pipe, as shown in FIG. 9C. This makes it possible to accurately measure the reciprocating flow of the fluid flowing in the pipe.

Next, FIG. 10A-10B shows a state of mounting when the implantable small flow sensor of the present embodiment is implanted in a rat, which is an experimental animal.
FIG. 10A shows a state after the implantable small flow sensor of the present invention is implanted in the rat airway.

  In FIG. 10B, after the implantable small flow sensor is implanted in the airway, the wire-like electrical wiring 4 is drawn to the back of the rat's head under the skin, and then pulled out to the outside at the back of the rat. It shows how it is.

  FIG. 11 shows the results when the exhalation inhalation characteristics in the airway during rat activity were directly evaluated with the flow sensor after the small flow sensor of the present embodiment was embedded in the rat airway. This result shows that the expiratory inspiration in the airway during the rat activity can be quantitatively evaluated by the implantable small flow sensor 3 of the present invention.

  The matters described in FIG. 1 to FIG. 7 are examples of the present flow sensor, and it is desirable to change the specific specifications according to the purpose of use. In addition, the target fluid of the present sensor is mainly gas, and any type can be applied as long as it is gas. Note that the present invention can also be applied to liquids such as blood and urine and solid fluids.

  As described above, in this embodiment, the two sets of heaters 12 and the thin film wirings 13 formed on the film substrate 11 have the same shape, and the thin film wirings 13 correspond to the flow of fluid flowing through the flow path 21. The two heaters 12 and the thin film wiring 13 are reversed under the same conditions even when the flow direction is reversed and the flow is reversed. As a result, the sensor output characteristics with respect to the fluid flow rate become the same without depending on the direction of the fluid flow in the pipe.

  In addition, a wire-like electrical wiring 4 is connected to an end portion of the thin film wiring 13 provided on the film substrate 11 using an anisotropic conductive film 15. Thereby, even when the implantable small flow sensor 3 is implanted in the airway of a rat (small animal), the wire-like electrical wiring 4 can be easily routed to the back part under the skin, and after being taken out from the back part. Highly reliable wiring can be taken out. As a result, the wire-like electric wiring 4 is configured to be taken out from the rat back to the outside of the rat after being routed to the rat back.

Further, the film substrate 11 is arranged along the inner wall of the pipe 30, thereby reducing the turbulence in the pipe accompanying the sensor installation to the limit.
(Other embodiments)
In the above embodiment, electric power is supplied from the outside of the rat to the heater 12 through the thin-film wiring 13 by the wire-shaped electric wiring. A receiver may be attached.

  Then, a microwave is supplied from the outside, the microwave is received by a wire-like electric wiring as an antenna, converted into electric power by a microwave receiver, and electric power is supplied to the heater 12 through the thin film wiring 13. . In this case, it is possible to exchange signals with the outside of the living body by using wire-like electric wiring used as a microwave receiver and an antenna, and it is configured such that the operation parts such as the hand and foot of the living body are difficult to contact. Yes.

Claims (3)

The flexible base material on which the heater is formed is mounted in a pipe arranged along a tubular organ in the living body through which the medium flows, and heat generated from the heater of the mounted flexible base material is transmitted to the medium. A flow rate sensor that measures a flow rate of a medium flowing in a tubular organ in a living body by detecting a state,
Each of the two or more heaters formed on the flexible substrate has a symmetrical structure having the same heating performance under the same conditions, and a linear member that supplies power to the heaters from outside the living body. By configuring a symmetrical structure having the same heating performance under the same conditions, the heat distribution by the heater and the linear member in the pipe is configured to be symmetric,
The living body implantable flow sensor, wherein the plurality of linear members protrude from the tubular organ so as to intersect the outside of the living body. The biological implantable flow sensor according to claim 1,
The living body implantable flow rate sensor is characterized in that a portion of the linear member that protrudes outside the living body is located at a position where the working part of the living body is difficult to contact. The biological implantable flow sensor according to claim 2,
The position where the living body implantable flow sensor is installed is an animal trachea,
An in-vivo implantable flow sensor, wherein an electrical wiring member connected to the linear member is taken out from the back of the animal to the outside of the animal.